Definition
The methylene blue value is an important indicator for evaluating the adsorption performance of activated carbon. It reflects the maximum mass or volume of methylene blue dye that can be adsorbed per gram of activated carbon under standard test conditions. It is typically expressed in milligrams per gram (mg/g) or milliliters per gram (ml/g).
The methylene blue value primarily reflects the mesoporous structure (2-50 nm) of activated carbon. Activated carbons with well-developed mesopores tend to have higher methylene blue values.
Testing Principle
Methylene blue is an organic dye with a molecular size of approximately 1.4 nm x 0.4 nm. The methylene blue value test utilizes the adsorption of methylene blue molecules by activated carbon. By adding a certain amount of activated carbon to a known concentration of methylene blue solution, thoroughly shaking for adsorption, and then measuring the remaining methylene blue concentration in the solution, the methylene blue value of the activated carbon can be calculated.
Applications
The methylene blue value is commonly used to evaluate the application of activated carbon in the following areas:
- Water Treatment: Removal of organic pollutants from water such as odor, BOD, TOC, dyes, pesticides, humic acids, etc.
- Food Industry: Decolorization, deodorization, purification.
- Pharmaceutical Industry: Adsorption of toxins, purification of drugs.
Relationship with Other Indicators
- Iodine Number: The iodine number reflects the adsorption capacity of activated carbon for small molecules, while the methylene blue value reflects its capacity for medium-sized molecules.
- Molasses Number: The molasses number reflects the adsorption capacity of activated carbon for large molecules.
Summary
The methylene blue value is a crucial indicator for evaluating the adsorption performance of activated carbon, aiding in the selection of suitable activated carbon for specific applications. If you have any further questions, feel free to contact us for support.
